There are a variety of digital communication networks wherein a main office or facility desires to conduct internet protocol-based communications with a branch office. Where this is effected using a T3 communication link, Ethernet local area networks at the respective offices may be required to connect with a T3 service unit (T3SU) by way of an expensive router using high speed serial interface (HSSI) protocol. It would be preferable for the customer to have the ability to couple the Ethernet LAN interface directly with the T3SU. A first problem in doing so is the fact that the Ethernet LAN operates at a first clock rate (e.g., 100 MHz) that is different from (higher than) and not synchronized with the T3 clock (44.736 MHz), making it necessary to provide some form of buffer interface between the two different clock domains.
A second issue is the fact that the size of the buffer is limited by practical considerations including semiconductor real estate availability, latency and cost—resulting in a buffer size that cannot accommodate more than just a few maximum length packets (e.g., packets on the order of 1.5 Kbytes (1536 bytes) long). This latter factor can be problematic where employed in programs such as Windows type file transfer protocol (FTP) programs, which entail relatively large file transfers, and may cause the limited capacity buffer to overflow, so that packets are dropped. Unfortunately, Windows type FTP programs do not readily recover from dropped packets, and TCP windowing, that would normally slow down the transfer rate until a maximum sustained transfer rate is realized, may fail—causing a further slowing down of the transfer rate and even stalls.